The facility in Kingston Broadway, which is owned by the council, had previously been allocated £120,000 of funding by the council for new changing rooms.
But further investigations have shown that more investment was needed as the boiler and air handling units also needed replacing.
In a report presented to Adur and Worthing Councils’ Joint Strategic Committee this week, it was noted that a failure to fund the works could lead to the pool being closed, causing financial and reputational issues to the operators.
Senior councillors were also informed that delaying aspects of the work would result in a greater total cost.
Faced with a £174,870 shortfall, councillors were advised to re-allocate capital funding previously approved for roofing and glazing and electrical rewiring works to take place at Impulse Leisure Centre in Lancing.
The report stated that these works would instead be deferred and that the issues identified could be managed in the short term ‘through reactive maintenance repairs as required’.
Councillors agreed to step in to provide the extra funding so that the works at Wadurs could go ahead at the meeting on Tuesday.
Following the decision, councillor Neil Parkin, Leader of Adur District Council, said Wadurs was a ‘popular and much-valued resource’.
He said: “Releasing this funding will enable the works to place within the coming months.
“While there will inevitably be some short term disruption, the end result will be a much-improved facility which will offer greater opportunities for people of all ages to learn a valuable life skill and keep fit.”
A council spokesman said Wadurs, which opened in 1993, had seen increased attendances and record delivery of lessons, with more than 900 pupils registered in the swim school.
But small cramped changing facilities at the pool have been causing logistical issues for staff and visitors, the spokesman said.
A single-storey extension will be built which will include 16 changing rooms, two of which will be suitable for families and people with disabilities.
A new office will also be created.
The work is due to start within the current financial year, the spokesman said.